First called a "BIKE JOCKEY STRAP" in the 1890s,it was sold to bicyclists to prevent NUT ACHES while riding a bike on bumpy, unpaved roads. BIKE became a brand name and there famous and popular garment was known by most as a JOCKEY-STRAP until about the 1970s when its started to be known as just a JOCK.
Jocks (or Athletic Supporters) were required equipment for all 7th. through 12 grade boys during P.E. class at most all of the nation's schools until about 1985 a trend toward loose nuts (the boxer rebellion) may have been the downfall of the JOCK-
strap in America.